[PR #7348/bf9d753e backport][3.8] 🐛 Fix RST in changelog template before links (#7349)

**This is a backport of PR #7348 as merged into master
(bf9d753).**

In corner cases, changelog fragments with things like detached link
definitions (example: #7346) cause RST rendering errors. This patch
corrects this by injecting empty lines between the changelog entry
bodies and their reference lists.

Co-authored-by: Sviatoslav Sydorenko <[email protected]>

Author: patchback[bot]

CHANGES/.TEMPLATE.rst

@@ -12,8 +12,8 @@
 
 {% if definitions[category]['showcontent'] %}
 {% for text, values in sections[section][category].items() %}
-- {{ text }}
-  {{ values|join(',\n  ') }}
+- {{ text + '\n' }}
+  {{ values|join(',\n  ') + '\n' }}
 {% endfor %}
 
 {% else %}